Conventionally, in an electric tool, torque of an electric motor is transmitted to an end tool constituting a driven object via a gear mechanism. In the case of such an electric tool, when the electric motor is started, a shock called starting shock is produced. To eliminate this starting shock, in an electric tool, a C-shaped torque transmission member capable of radial elastic deformation is provided between two rotary members in a torque transmission system (See, for example, Japanese Laid-Open Patent Publication No. 2002-264031). When transmitting the rotation of one rotary member to the other rotary member, the torque transmission member undergoes elastic deformation in a radially outward direction so-called diameter enlarging direction depending on the load on the driven side, so that the starting shock is mitigated, and the electric tool is improved in terms of durability and feel of use.
In the above-described conventional electric tool, the end portions of the torque transmission member and abutment surfaces of the rotary members for contacting with the end portions are brought to contact with each other in a face-to-face contact state. As a result, the torque transmission member does not easily undergo elastic deformation in the diameter enlarging direction, making it difficult to mitigate the starting shock in a stable manner.
Therefore, there is a need in the art for an electric tool capable of mitigating the starting shock in a stable manner.